Semiautomatic telephone system



Patented May 27, 1930 [units s PATENT? orrrcr 7 p FERNAND PIERRE noeusrmcononnn, or rears, FRANCE, ASSIGNOR ro'AU'roMArIo nnncrnrc INC", on cnrcneo, rumors, njconroan'rron or DELAWARE SEMIAUTOMATIC TELErrronn srs'rEM Application filed June 15, 1928, Serial at. 285,539, and in France September 23, 1927.

The present invention relates to telephone systems in general, but is concerned more particularly with [semi-automatic telephone systems, which systems are characterizedby the fact that'connections to and-from telephone lines are set up by automatic switching equipment under'the control of an operator. v

More in particular, the present invention concerns itself with a telephone system wherein operators at a central point may control the switching equipment in a plurality of outlying exchanges terminating local-battery magneto lines.

In the inventionas illustrated in the accompanying drawing and described herein, the central manual exchange is connected with a remote semi-automatic exchange by means of a number of trunk lines, each of which terminates at the semi-automatic exchange in a switching link comprising'two rotary-type switching mechanisms.

According to a feature of the'invention, one of the two rotary mechanisms, above mentioned operates asa finder switchto find the calling line when a call is made. In case the call is for another line of the same semiautomatic exchange, the operator maycontrol the other switching mechanism to extend a connection to the called line, retaining supervision over the connection through the inter-exchange trunk line. 7

The one of the two switchingmechanisms of a pair that operates as a finder to find a calling line is used also as a connector to extend a connection to a called line under the control of operator when the operator is extending a connection to a line of a semiautomatic exchange from'the outside, and it is a feature'of the arrangement that the oom bined finder and connector switch doesnot restore at the end of a call, but remainsin the position last'used, so as to avoid 'giv ingthe priority of choice to the same linesin all cases, and is returned automatically to its normal position only when taken for useiby the operator to complete a call from the manual exchange to a line ofthesemi-automatic exchange. 1 I

A further object of the invention the subscriber may operate his hand generator to slgnal the operator at a time when all trunk lines between his exchange and the manual exchange arebusy and. be signalled when the operator responds-and appliesringing current, as she does ineach case-to cause the a normal position and also. two dead positions corresponding to O and .00 on which the wipers stop. in casetheline called has: a two digit designation (05, for example) or a three-digit designation (O05, for example). By the present arrangement,,the operation of the connector remains under thecontrol of the operator .until she. has finished the. setting and has projected ringing" current to signal the called station, whichlatter opera tion connects up the wipers of the connector and removes it from under the control of further impulses. 1 It is afurther object of the invention to arrange the connections associated with the trunk lines between the manual exchange and the semi-automatic exchangeso that the bat- .tery which supplies current in the'sjemi-automatic I exchange for the. operation of they switching apparatus therein is. continuously chargedifromithe battery the manual exchange over each idle interconnecting trunk line. I I

A feature ofthe' invention is that the relay which is bridged across thesemi-automatic exchange end of each trunkand which has its midpoint suitably connected to the battery in the semiautomatic exchange to enable the shunt-field type disclosed ini'Patent 1,544,300,

provision of circuit arrangements whereby a granted June 30, 19:25, to Charles J i Erick- V ..:soa',' andthat the cur ent tra es. h' d-- 10o -ator throws her ringlng key.

The accompanying drawing shows one embodimcnt of the invention by means of the usual circuit diagrams.

This drawing shows the trunk line TL connecting the manual exchange with a semiautomatic exchange. The drawing shows in the manual exchange the jack J and othe r terminating equipment of the trunk line TL and the cord circuit CC at the operators switchboard Y In the semi' automatic exchange the draw ing shows the terminating equipment of the trunk line TL, which comprises the main connector and theauxiliary connector, together with the associated relays." In the semi-auto matic exchange, there-is shown the line circuit LC associated with the line of the local-battery magneto substation SS;

Each of these connectors is of the well known rotary type whosewipers move in a forward direction only and are advanced upon the back stroke of the stepping magnet.

,Detailed description detaileddescription of. operation of the apparatus shown will'now be given. It will first be dcscribedhow the battery at the manual exchange charges the battery at the semi-automatic exchange over thc'trunk line TL when this trunk llI1 e lSl idle, it being understoodot' course, that the semi-automatic exchange battery is similarly charged over any one of the other interconnecting trunk lines that are idle. j y

Charging the battery at the sewn-automatic exchange It will be noted that thereare several battery symbols in the semieautoinatic exchange each indicating a battery with. the 4 positive pole grounded and the negative pole free. It

,willbe understood, of course, that each of these symbols represents the; same battery.

It will be noted further that there are sev-- .eral batterysymbols the manual exchange,

each indicating a batterywvith the positive .pole grounded and, the negative pole free. It will beun'derstood likewisetha'jt each ofthese V (p symbols in'dicates the samefbattery; This wan -henna of substation SS, test relay 5, battery inthe manual exchange is designated B1, as distinctfromthebattery B2 which has I its negative poleigrounded'and the" positive pole free for a purpose whichffwillbe de- "scribedjhereinafter. 3 In'each or; the symbols 'ofl'the battery in; the semi-automatic exchange, onlyione cell"is '-indicated,' while in 'matic exchange battery.

- Current is normally flowing from the battery in the manual exchange over the two conductors of the toll line TL in parallel, passing from the battery Bl through the'lamp L, upper winding of relay 13,.armature 122,

and the two windings of coil'llin parallel,

' tothe'trunkline. '.-In the semi-automatic exchange, current flows from the two conductors of thetrunk line TL-in parallel through the two windings of theshuntfield relay 3 in parallel, armatures- 61 and 71, right hand winding'of shunt field relay 9, and armature 92 of relayS to the semi-automatic battery, relay 9 being normally operated as shown.

It will be noted that relay 13 in the manual exchange is normally operated, maintaining thecircuit of'the drop D1 open. I

The subscriber at substation SS operates his hand generator Gr, causingringingcurrent t o'be projected over'his line to the exchange, operating the bridged relay'A; Re-

.laylrlocks itself to the start conductor at its lower armature, at the same time placing a negative potential on the associated test con- "ductor in thebanks of the automatic switches through the winding ofthe'cut ofi relay 3.

Assuming that the connecting pairshown in the drawing is idle, startrelay 6 thereof operates over the start conductor'andthrough resistance R3 in series with the lower win-ding of relay- A. The start" relays. of any =other connecting pairs that happen to be idleials o' operate, the arrangement being such thatf t-he finders of all idle'connecting pairs search simultaneously for any calling line. Upon operating, relaysf6,ja't armature 63, closes a circuit from ground at" armature 51' through the self-interrupting contacts'for'the rotating ma 'gnetgRlofthe main connector,-

whichj connector is nojiv to operate as a finder.

The magnet R1 operates in a buzzer-like manshowniinthe 'drawing'isthe first to connect which is I connected through arinaturehil. of

relay 6 to test wiper'Tl, operate s"in series with' the'lower winding of euteofi' relay'YC,

through the upper." contacts iot relay A.

Upon "operating, relay 5,: opens the circuit of steppingmagnet Rl at armature-51- and short circuitsrelay 6. *Thepresence of resistance "ation 'fromsh'ort circuiting the s'tart relays oftheo'ther c'onnectingpairs. Relay 6is' a slow acting relay onfaccount'ofthe'copper collar, indicated by the usual symbol'fi andalsobecause itis short circuited, forwhich finder from stopping'thereon. "Rela f change so that when relay A. falls back he 'sp'onsive to the opening ofthe' startcircuit the "two windings of relay- Cins'eries'are'conducing the test potential thereon. s

It will'be noted that relay 7, one terminal ofwhichis grounded through armature 21 of" "relay 2; is inseries with the stepping magnet R1 and the interrupter contacts "thereof through armatures' 64 I and 68 "subsequent-to i the operation ofirelay 6. (It will benoteclfurther that relay '7, however, is short circuited at armaturehl'until relay5 op'erat'es;whereupon relay 7 operates'iuse'ries with magnet R1. "MagnetR-l d'o'esnot' operate'at-thistime on account ofthe relatively? high" resistance of relay TL; this loeingdone only momentarily d'ur-- In the manual exchange, relay 13*fallsback when the charging cir'cuiti's opened and-closes 1 Q 4. a circuit forthedr'o'p 'Dlfwhich operates to signal the operator. 1.

" When relay 6 falls'ba'ck'to' reestablish the 'frelay 9 and through the two parallelcircuits a fto ground above mentionedfwhereuponre- "l'ay 9 reoperates' and reestablishes" the pie "Viously traced charging circuit. -Itis--as- "Is'umed' that relay 1 "does not operate--' in the its circuit.

v 7; At-"armature 73; relaylT'lo'cks itself to the magnet R1-independentoificontacts 63; and 64; at armature 72 it shunt-s armatu're 620i relay 6; and=atarm'ature 71 it opens the circuit 'thro'i'lglrwhich the local jbattery' is being'charged oyerthe trun-k'line fthe" auxiliary tea-meter preparator "t operation of the aux1ll-ary connector "i'n fcase Whenthe 'operator"notesthe operated condition of thedrop D1,she inserts the plug :At theu er auxiliary contacts of the jack a circuit'is closed for relay 12,' and at'the'lowfreas'on it does not fallback immediately. Re lay 5," at its lower 'arinature; short circ'ui'ts' its 'lower winding so asto re'duce'the testpote'n- 'ti'al onthetest conductor ofthe line "offsub "station SS sufficiently to prevent any-"other battery 132 through contacts" of the calling device key K. When relay 12"ope'rates, it

closes a holding circuit" through the lower L *windingof relay 13' at armature 121","a'1'1d' at theline circuit LC operates in series with testrelay 5-a'ncl disconnects the upper winding of line relay at-its upper armature; opensthe sta'rt' 'circuit'at its lower armature; and its F inn'er'upper armature 'it makes" a circuit F armature 122 it disconnects the impulse leg device contacts to the battery B2. Current now flowsoyerthe'trunk'line TL in the 'reyerse'direction, causing relay 9 in the semiautbrfiatic exchange 'to" restore "connect nected to the test conductor; still further 're- 'up'relay 1 and theresis't'ance 'R5 i1rpam1-1e1.

? Relay lop'erates and closes" a' circuit for reilay 2' at armature ll th'rough magnet B1 and the associated interrupter contacts thereof? Relay 2 operates, but it is of sufiiciently}high resistance to prevent the bp'e'rationbf magnetRl. Atarma'ture23, relay 2 remoi' esre- "sista'n'ce R5 'fr'om in shunt" of i'elay 1" and places another short circuit around start'reflay 6. At armature 22, relay 2"lofc ks"itself energized independent for armature 11, I through armature 82, 'IibirI n'al. At armature 21; 'iela'y amines round on" locking confd'uctor69'; at the "same time'openingthe cir- 5 euit'oi' relay 7. Relay 7 iallsba'ckjbut this is witho-iit"particularresult at this time "as the functibnof armatureninete n;taken over by the locking circult through armaturesee andh? lnser'ies.

Having 1ug'ged*i "the operatormani l'at'es' theiunging key of theco'rd' circuit 00, whereby projecting ringing current "through the jacks and cx' erthetrunk line TL through the two" windings in sef'ies "ofthebridged re- 5 When current 'flow's through the two and a parallel circuit for the lower winding I of relay 10through theresistanceR6; Relay '8 operates at this timeQbut'frelay- 10] does not k v operate because itslo'wer winding isshcrt"c'ir- '-'ioharg1ng circuit; 1t-=clos'es'ac1rcu1t through cuited at the ass'ociated off-normal "contacts of the auxiliary connector. U pon operating, relay 8 locks its 'lowefwinding to" conductor wiiidi ngs 'in series; of rela s; n'iagnetic fiux 'set-iipwhicli'passes through the two" windcores' paralleltof the armature circuit -'(not"show1'1)',' operating the armature to close 569 at F Chntacts' 81 at contacts" 82" ititra n sfers 7 the locking circuitofrelay ircni iha gnet t p I TR-lot the main coniiectorto magnet-7R2 of V grime required for'relay'9'to pu11-upandcen iliary connector. Relay operates and-pie pares to lock its upper winding to conductor cuit of the called line isa duplicate'of the line circuit LO" of the substation SS. The relay corresponding to relay A operates in the line circuit of the called line and completes the circuit of the relay corresponding to relay C, thereby completing the locking circuit of relay 1O. The cut-0E relay of the called line circuit thereupon pulls up and removes the associated line relay from in bridge of the line. 1

It'will'be noted that ofi-normalcontacts of the auxiliary connector have removed shunts from around the condensers in the talking branch leading to the wipers of the main connector. These condensers confine the ring ing current for the most parttothe intended channels when the operator rings after having set the auxiliary connector on the desired line. This is of utility in case the calling subscriber does not replace his receiverwhile waiting for the operator to complete the connection, In case the receiver has been replaced, the calling subscriber is recalled by the portion of the ringing current which passes through the above-mentioned condensers.

When the called subscriber responds, conversation may take place: At the end of the conversation, the two subscribers are expected to operate their generators to give the clearing out signal by operating the drop D2 of the cord circuit CC.

When the" operator withdraws the plug from the jack J, relay 1 falls back and relay 9 reoperates to reestablish the charging circuit. Relay 1 short'circuits relay 2, which relay falls back and closes the restoring circuit of the auxiliary connector at armature 21 through oft-normal contacts ofthe auxiliary connector. The auxiliary connector is restored to normal in the manner hereinbefore pointed out. Relays 8 and 10 fall back when ground is removed from conductor 69 at armature 21.

Call incoming to the semiautomatic exchange It will now be assumed that the operator at the manual switchboard receives a call for the line of substation SS at the semi-automatic exchange. Assuming that' this call is received on the unshown plug of the cord circuit CC, the operator inserts the shown plug there'- of into the ack'of an idle trunk line, the jack J of the'trunk line TL for example, whereupon relay 12 operates to open the charging circuit and to establish a reversed-current circuit from the battery B2 over the trunk line TL. This resultsin a deenergization of relay9 and in the operation of relayl. When relay 1 operates under this condition, test re-' lay 5 of the main connect-or has not been operated and relay 2 is, therefore, short circuited through the back contact of armature 52 off-normal contacts ofthe main connector, and the back contact ofarmatur'e 22. The connection of the short circuited relay 2 to the magnet R1 of the main connector through the self interrupting contacts thereof results in the step-by-step advance of the main connector until the short circuit is removed'from around relay 2 at the off-normal contact of the main connector when it arrives in its normal position, whereupon the stepping operation ceases and relay 2 energizes in series with magnet R1 andprepar'es an operating circuit for the magnet R1 at armature 22, at the same time opening afurther point in the restoring circuit of the'main connector. At armature 23, the relay 2 renders the start relay 6 nonresponsive to control over the start conductor by short circuiting it.

Now, when the operator dials the digit or digits in the desired number, line relay 1 falls back each time its circuit is opened 'atthe calling device CD and closes at armature'll a circuit for magnet R1 through the operated armature 22 andthe armature 82, normal. Magnet Rl'responds'to these impulses and advances the wipers, of the connector into engagement with the line of substation SS.-

The operator now applies ringing'current to the trunk line TL,.operatinglrelayi 3 'to close a circuit for relay 8. Relay 10, as'he're-' inbeforepointed out, is short cir 'cuited at'this time and does not respond. Relay 8 responds and locksitself to "conductor 69 at armature 81. Atarmature 83, relay' 8'conn'ec ts the test relay 5' to the test wiper for" the first time during this operation, with the. result that relay 5 operates in series with relay 0 as soon as relay A has operated and connected relay C to the test conductor. ,RelayC. disconnects relay A from across the talking circuit.

When the called subscriber responds, he

'may. converse with the calling subscriber through the connection setup throughthe cord circuit CO and over-the trunkline'TL.

When the operator receives theusu'al ring ofl' signal onthe drop D2, shepulls down the connection, whereupon relay 9 operates to reestablish" the charging circuit and cut off'relay 1. Relay 1 fallsbackin this" case and short circuits relay 2, thereby sending an impulse through'the operated armatu'res 22and 82 and armature 101 to theniagnetR2 of the auxiliary" connector as" hereinbefore described. Relay2 falls back after aslight interval and 'opensthe circuit just traced, at the same time removing ground from looking conductor 69'an'd closing the restoring circuit of theaux-iliary connector at'armature 21.

Relay 8 falls -bac'lr becauseconductor69-is Miscellaneous trunk line. The grounded condition is indicated inthe manual exchange by the glowingofthelampL.

What is claimed is:

1. In a combined manual'and semi-automatic telephone system wherein a trunk line extending from the manual exchange to a semi-automatic exchange terminates at the semi-automatic exchange in a permanently associated finder switch and in a permanently associated connector switch, means con trolled over a calling line for operating the.

finder switch to connect theassociated trunk line with a calling line, and means controlled over said trunk line from the manualex; change for setting the permanently connected connector'switch on the contacts of a desired called line to complete a desired connection. 2. In a semi-automatic telephone system wherein telephone" lines are accessible toa finder switch and also to a permanently associated connector switch, operator-controlled means for setting said connector switch on any accessible line desired by a calling subscriber whose line is connected with by said finder.

In a semi-automatic telephone system, a connecting link comprising a permanently paired finder switch and connector switch both having access to the same plurality of subscribers lines, a control line extending to a control point, means responsive to the finding of'a callingline by said finder for signalling the operator at said control point over said control line, and means controlled by an operator at said control point over said controlled line for operating said connectorto complete the connection from the calling linefound by said finder to a desired called line. 7 i

4. In a telephone system, an automatic connector switch having normally disconnected Wipers, means under the control of a calling party for transmitting impulses to said connector switch to advance said wipers into engagement with the contacts of a desired line, and means responsive to an application of ringing current to said connector switch to connect up the wipers.

5. In a telephone system wherein connections are completed through the medium of automaticswitching mechanisms, a line 1m ing a given designation, another line having the same designation plus an additional designation and means responsive to the transmission ofthe respective designations to said automaticswitching mechanisms for setting up a connection to either line whose designation is transmitted.

6; In a telephone system employing a coin -nector switch of the adding type, means complete a connectionfrom the calling line to the desired called line only. 7 v

7. In a telephone system employing automatic switching mechanism, a finder switch having access to a plurality of lines and ar ranged to stand normally in any arbitrary position, means including a trunk line extending to said finder for seizing said finder as a. connector to complete .a connection to a desired one ofthe lines to which'the switching mechanism has access, and means responsive to the seizure of said finder under this condition for advancing it to a predetermined position preparatory to its operation as a connector.

8.In a teleplione system wherein connections from calling lines are set up through automatic switchingv equipment, magneto substations on said calling lines, means responsive to an application of ringing current to. a calling line from a magneto substation for operating automatic switching apparatus to setup a connection between the calling line and a switching point,.and means for signalling the callingrstation by ringing currenttoinform him that the connection is set up. r

9. In a semi-automatic telephone system wherein connections are set up from calling magneto lines. to a manual switchboard means responsive to an applicationofringing current to the semi-automatic exchange from'a calling magneto line for setting up a connection from the calling line to said manual switchboard, and means for signalling the calling subscriber by means of ringing current transmitted from said manual switchboard when the operator responds.

10. In a telephone system, a trunk line'extending from a manual switchboard in one exchange .to a second exchange, a storage bat-' tery in the second exchange, circuit connections for charging the storagebattery inthe second exchange over said trunk line from a current source in-the first named exchange, means responsive .to the taking for use of said trunk line in the secondexchange for Luv stopping the flow of charging current over said trunk line, and means responsive to the cessation of charging current over said trunk line for signalling the operator at said manual switchboard.

11. In a telephone system, a trunk line connecting two exchanges and arranged to be used for talking purposes, a storage battery in the second exchange arranged to be charged by a current flow over said trunk line from a current source in the first exchange when the trunk line is not in use for talking purposes, and means including a switching device in the second exchange operative responsive to a shunting of the charging circuit over said trunk line for disconnecting the storage battery in the second exchange from the charging circuit so as to prevent a discharge of the said storage battery.

12. In a telephone system, a trunk line connecting two exchanges and arranged to be used for talking purposes, a storage battery in the second exchange arranged to he charged by a current flow over said trunk line from a current source in the first exchange when the trunk line is not in use for talking purposes, means including a switching device in the second exchange operative responsive to a shunting of the charging circuit over said trunk line for disconnecting the storage battery in the second exchange from the charging circuit so as to prevent a discharge of the said storage battery, and means for automatically reestablishing the charging circuit through said storage battery when the shunt is removed.

13. In a telephone system two exchanges, automatic switching mechanism in the second exchange, a storage battery in the sec ond exchange, a source of charging current of one polarity in the first exchange for charging the storage battery in the second exchange over said trunk line, a source of operating current of a difierent polarity in the first exchange, means responsive to the connection of the charging source to said trunk line for switching the trunk. line into connection with said storage battery so that the storage battery is charged. over the trunk line from the charging source in the first exchange, and means responsive to the substitution of the operating source for the charging source for disconnecting the trunk line from the storage battery and for preparing an operating circuit for the automatic switching mechanism.

14. In a telephone system, a trunk line, a relay having two windings Wound on the separate parallel cores and a single armaturereturn magnetic circuit, said windings being connected in series with each other and in bridge of said trunk line so that current impressed on said windings from across said trunk line results in aparallel magnetic flow through the two cores of the relay to attract the armature, and a circuit over the two con- 

